Increase In Material Removal Rate Research Articles

Evaluation of machining performance and multi criteria optimization of novel metal-Nimonic 80A using EDM

This study focused to machine novel Nimonic 80A through Electric Discharge Machine process. The process parameters are optimised to achieve high surface integrity along with high material removal rate (MRR) with minimum energy consumption. Central composite design along with analysis of variance technique has been applied to make correlation between the process parameter and responses. The developed model of surface roughness shows that the peak current and pulse-on time have significant effect whereas; a little effect of pulse-off time. The said result may be obtained due to simultaneous action of deposition and notching (removal) of material in order to form crater. In case of MRR, the pulse-on time and peak current are found as significant factors with increasing trend (i.e. when the input values are increased the MRR increases) whereas; a reverse trend is noticed with pulse-off time. The optimum values for maximum MRR (0.512444 gm/min) and minimum surface roughness (7.82203 µm) with 81% desirability are obtained for the process parameter as 13.49 A peak current, 150 µs pulse-on time and 4 µs pulse-off time.

WITHDRAWN: Micro machining in biological perspective – Critical review

• This article discusses the importance of bio machining in modern manufacturing process. • Importance of different micro organism in machining aspect and its capabilities are discussed in details. • Importantly, the available of mechanism equation and modelling is discussed and presented. • The benefits of various parameter on reducing the surface roughness and increasing material removal rate are discussed in detail. Micromachining process is one of the versatile process in making miniature components for different application. Miniaturization is playing a vital role in reducing the size, shape and density of the part. Microfabrication and further machining are the only way to get the desired shape and size. This paper reviews the importance of biological kind of micro machining process in terms of its capability, advantages and future scope in this area are discussed and presented. The article is discussed in the following order, overview of the bio machining process; it summarizes the possibility of bio machining process, subsequent section covers the progress in bio machining, principle mechanism deals with direct and indirect mechanism of material removal. Finally, the scope for the future work is discussed and presented.

Rotary ultrasonic-assisted abrasive flow finishing and its fundamental performance in Al6061 machining

The geometric complexity of 3D-printed parts increases the difficulty of surface finishing with the conventional grinding technique. In this study, a rotary ultrasonic-assisted abrasive flow finishing (RUA-AFF) method is proposed towards improving the performance of the AFF process by providing rotary motion and ultrasonic vibration to the equipment. Finishing experiments are carried out involving Al6061 to investigate the capabilities of the proposed RUA-AFF. The obtained results show that (1) the higher ultrasonic vibration amplitude results in the greatest improvement in the work surface quality and a higher increase in material removal rate (MRR); (2) with the higher ultrasonic frequency and rotational speed, the surface roughness and MRR are decreased marginally; (3) there are two material remove modes in the RUA-AFF process: abrasive impingement and micro-cutting. These indicate that the high efficiency and high-quality finishing of Al6061 can be performed with the proposed RUA-AFF technique.

Effect of pulse current in manufacturing of cardiovascular stent using EDM die-sinking

This paper proves that die-sinking electrical discharge machining (EDM) is an alternative and attractive manufacturing method of producing cardiovascular stent. This study investigates the effect of pulse currents on the material removal rate (MRR), the surface of EDM, and the upper surface of the strut stent. The observed surface characteristics of the strut were surface roughness, recast layer, and the diameter of the crater. The recast layer and crater were analyzed by an optical microscope, and the surface roughness was measured by a surface profilometer. The pulse currents which were used in the manufacturing of stent by die-sinking EDM were 1.5 A/45 μs, 3.0 A/90 μs, 4.5 A/120 μs, and 6 A/150 μs. The experiment shows that the stent is successfully manufactured from minitube AISI 316L by die-sinking EDM. The diameter, length, and thickness of the stent are 4 mm, 20 mm, and 0.3 mm, respectively. The results show that increasing of pulse current will cause the increase of MRR, the thickness of recast layer, the surface roughness, and the crater diameter. The MRR, thickness of the recast layer, surface roughness, and crater diameter are also influenced by the pulse on time. The EDM surface roughness, the average thickness of recast layer, and the diameter of crater are in the range of 3.49–9.53 μm, 17.6–97 μm, and 75.84–276.5 μm, respectively, and the upper surface roughness of the strut is 0.5534 μm. The best quality of the strut is generated from the pulse current 1.5 A/45 μs.

Parametric effect on material removal rate and surface roughness of electrical discharge machined magnesium alloy

Magnesium and its alloys play a vital role in various applications such as automobile, aircraft, biomedical and military etc. Mg alloys have superior characteristics such as light weight, high strength, good damping capacity and easily castability etc. Eventhough it has attractive range of properties, the machining of magnesium alloys using conventional machining methods is difficult. To overcome that issue, non traditional machining is considered as a potential process. EDM is an electro thermal process extensively used for machining hard materials. In this investigation, the ZE41A magnesium alloy is machined using EDM with copper electrode. In order to improve surface characteristics such as material removal rate (MRR) and surface roughness (SR), various parameters namely current, pulse on time and pulse off time were selected. The regression values of MRR and SR are 97.20% and 99.62% respectively indicating an empirical relationship between the parameters and responses. Pulse off time was found as a significant parameter on the response followed by pulse on time and current. MRR and SR increased with increasing current, pulse on time and pulse off time. At a current of 5A, the produced spark density is high so that the removed quantity of material from the workpiece is high. At a pulse on time of 95 μs, the spark intensity is high affecting the local temperature in the machined zone, and hence MRR increases. SR drastically increases at increasing current. At higher current, large size crater are observed on the machined surface that made the surface rough, and hence SR increases.

Evaluation of a novel approach for considering damping effects in a process force model of a geometric physically-based milling simulation

Process damping in milling is a significant influencing factor in avoiding detrimental dynamic effects such as regenerative chatter vibrations, which can impair the workpiece quality and increase tool wear. In this context, the use of tools with flank face chamfers causes significant process damping effects over a wide range of spindle speeds. This way, processes with increased material removal rates due to high radial and axial tool immersions can be conducted without the occurrence of disturbing chatter vibrations. A precise prediction of the process stability is necessary to define efficient process strategies in advance. However, this is particularly challenging in the presence of process damping due to its nonlinear process behavior. This paper presents an evaluation of a new approach towards modeling dynamic forces in a geometric physically-based milling simulation for taking process damping effects caused by chamfered cutting tools into account. This model considers the vibration velocity present at the cutting edge in order to calculate a damping force caused by the dynamic tool-workpiece contact. The parameterization of the velocity-dependent force model was carried out a priori by conducting finite element simulations using an orthogonal cutting model as an analogy setup to determine the resulting force components. The proposed modeling approach was analyzed by comparing the simulation results to corresponding milling processes for validation. In contrast to established empirical force models, which calculate the process forces entirely as a function of the undeformed chip shape, the consideration of the dynamic tool-workpiece interaction led to a significant damping of the modeled process vibrations.

Experimental modeling and optimization of magnetic field assisted electrical discharge turning: Applicable for wind power turbine elements

Electrical discharge turning (EDT) process is finding its application in machining of rotary elements that is usually difficult to be machined with conventional processes. In order to perform the process more efficient, in the present work a new modification through assistance of magnetic field with EDT process was adopted. Here, an experimental study was made to investigate effect of magnetic field assisted EDT parameters i.e. magnetic flux density, current, pulse time and spindle speed on performance measures i.e. material removal rate (MRR), overcut (OC), surface roughness (Ra), recast layer thickness (RLT) and hardness (H). Number of 30 experiments were carried out using face-centered central composite design taken into account three levels for each parameter. Empirical models were developed using regression analysis with 95% confidence level to correlate relationship between inputs and outputs. Analysis of variances was also carried out to check the adequacy of developed model and to identify which factor has greatest influence on performance measures. Finally, desirability approach function was utilized for multi-objective optimization of process taking into account maximum MRR and hardness as well minimum overcut, surface roughness and recast layer thickness. The research findings indicated that discharge current and pulse on time are most influential parameter on MRR and H; while, magnetic flux density has greatest effect on OC, Ra and RLT. Effectiveness of magnetic field assistance showed that this parameter results in 56% and 38% increase in MRR and H, respectively; also, it results in 31%, 43% and 47% reduction of overcut, surface roughness and recast layer thickness, respectively. Finally, the optimization results demonstrated that magnetic flux density of 0.4 T is an optimum value, however, upon the condition of roughing or finishing, the remaining parameter setting should can be changed.

Effects of functional alkali in magnetorheological finishing fluid

Magnetorheological (MR) fluids can be utilized for ultra-precise finishing, for instance, in fused silica (FS) optics in giant laser system. However, few modification methods of MR fluid can improve the material removal rate (MRR) and surface quality of the finished optics simultaneously. In this study, we investigated the application of functional alkali additives in MR finishing fluid. MRR was doubled over the untreated MR fluid; meanwhile the surface roughness of the FS converged to 0.44 nm. Such excellent finishing performance can be mainly attributed to the dual functional effects of the triethanol amine (TEA) alkali, the hydroxides released by TEA contributes to the MRR increase and the steric hindrance effect of the ethanol ligands helps improve the surface quality.

Process parameter optimization on EN8 steel in Electric Discharge Machining (EDM) using Response Surface Methodology (RSM) Technique

Electric discharge machining (EDM) is widely used in the manufacturing sector due to its exceptional machining attributes and high fastidiousness, which could not be accomplished via other conventional machining. The research work aims at analyzing the optimal machining parameter and to reduce the machining time by varies in an increase material removal rate (MRR) and productivity and low tool wear rate (TWR). The parameters of Peak current, Pulse on time, Di-Electric Pressure and Tool diameter are varied. The usage of variance analysis (ANOVA) optimized parameters are determined by way of doing diverse dry runs the usage of Response Surface Methodology (RSM) approach and the mistake percent can be mounted and parameter contribution for MRR and TWR have been also observed.

Experimental investigation on electric discharge drilling of titanium alloy (Ti–6Al–4V) with a gas-aided rotary tool

In this study, the authors tried to make holes in a titanium-based superalloy by a completely new machining method called electro-discharge drilling (EDD) using a gas-aided multi-hole rotating tool. Successful machining of the titanium work samples is extremely challenging due to its extreme hardness and stiffness. One of the key challenges facing the EDD operation is the elimination of spark-eroded matters from the electrodes gap. Arcing happens when the trash is collected in the working passage, which adversely affects the performance of the EDD. In this study, an effort has been made to explore an active flushing mechanism that can improve the flushing activity during the EDD process. Computational fluid dynamics analysis suggested that successful internal flushing by multi-hole rotating tools might result in the efficient removal of the molten material from the electrodes gap. In addition, in this study, a comparative assessment of the EDD with the gas-aided multi-hole rotary electrode and the EDD with the stationary solid tool was carried out taking into account significant EDD responses. Besides, it was observed from the investigation that increased material removal rate and reduced EWR as well as surface roughness were acquired in the EDD with a gas-aided multi-hole rotating electrode in comparison with the EDD with a conventional stationary solid electrode. Basic analysis of surface morphology indicates that the development of recast layers and surface cracks is not very likely to occur on specimens machined with a gas-aided multi-hole rotating electrode in comparison with a workpiece machined with a conventional stationary solid electrode. The results indicate that the use of pressured argon gas in EDD with a gas-assisted multi-hole rotating electrode has a beneficial effect on the execution of the procedure.

Local mean decomposition and artificial neural network approach to mitigate tool chatter and improve material removal rate in turning operation

Productivity has always been a major concern in the industry. It can be improved by increasing material removal rate. Regenerative chatter during machining is the major obstacle to attain this. In the present work, a methodology has been proposed to select a proper combination of input cutting parameters for stable turning with improved metal removal rate (MRR). Chatter signals generated during the turning of Al 6061 have been acquired using a microphone. Initially, acquired signals have been processed using local mean decomposition (LMD) signal processing technique. The decomposed signals have been analyzed using different statistical chatter indicators considering Nakagami distribution approach for ascertaining the thresholds of chatter severity. Prediction models of most effective statistical chatter indicator and MRR have been developed using an artificial neural network (ANN). Moreover, this prediction models have been optimized using multi-objective genetic algorithm for ascertaining the optimal range of cutting parameters for stable turning with higher MRR. Finally, obtained stable range has been validated by performing more experiments.

Recent developments and applications of chemical mechanical polishing

This article discusses advanced developments and applications of chemical mechanical polishing (CMP) published recently in the selected papers indexed by Web of Science. The topics covered are advances in slurry and abrasives, pads and conditioning, CMP for semiconductor device manufacturing, CMP for other applications, modeling and simulations, and CMP with ultrasonic vibrations, lasers, photocatalysts, or UV lamps. Nonspherical abrasive particles have been developed for CMP, resulting in increased material removal rates (MRRs). Advanced conditioning methods have been proposed to uniformly generate pad surface shapes. Fixed abrasive CMP has advantages with higher MRRs. New models for designing the pad and conditioner have been proposed, and more uniform pad shapes can be obtained. Integrated advanced process control improves the wafer-to-wafer variation. Dental implants treated by CMP perform equally or better than the baseline-machined implants and the biphasic calcium phosphate-treated implants. The slurry distribution and the abrasive behavior can be simulated by means of multiphase modeling. Molecular dynamics simulations can explore the mechanism of CMP. CMP of wafers can be simulated using an atomic force microscope with its tapping mode. Theoretical models have been developed to calculate removal depths, study the chemical action in CMP, and explore the crystal orientation effects. CMP assisted by ultrasonic vibrations increases CMP MRRs and lowers the roughness of polished surfaces. CMP assisted by using UV lamp power, femtosecond lasers, or photocatalysts enhances CMP MRRs.

Experimental Investigation into electric Discharge Machining of Ti-6Al-4 V ELI alloy: An insight into biomedical applications

Ti-6Al-4 V-ELI alloy is acknowledged for its biomedical use. In non-traditional machining method like Electrical Discharge Machining, the material removal is through electro-thermal action with no direct contact between tool and work-piece. The emanation of spring-back effect apart from adherence of alloy results with poor surface finish. The same is nullified with the current EDM method by using effect of electro-thermal energy applications thereby achieving close tolerance. The effect of input parameters such as Voltage (V), Current (I) and Pulse on-Time (Ton) on Material Removal Rate (MRR) and Surface Roughness (Ra) was investigated. The Ton was varied between (60&70)μs, voltage of (50&55) V and peak current of (10&12) A. The analysis of result was carried out with 23 factorial degree of experiment and the response contributing highest effect was noted. The MRR, Ra and electrode wear increase with each process parameters. It was found that factors like V, I and Ton have significant effect to varying degrees on MRR and Ra. MRR increased with increase in Ton while Ra increase with decreased in voltage.

Finite element simulation-based predictive regression modeling and optimum solution for grain size in machining of Ti6Al4V alloy: Influence of tool geometry and cutting conditions

The present research study was aimed at studying the impact of machining parameters on grain size alterations in machining of Ti6Al4V alloy using finite element analysis (FEA) based on the Johnson-Mehl-Avrami-Kolmogorov (JMAK) recrystallization model. The machining parameters consisted of both cutting conditions and tool geometry including cutting speed, feed rate, tool edge radius and rake angle. Three series of JMAK constants were used in the simulations and the degree of accuracy of the obtained results were compared. Finite element (FE) simulations were conducted for machining conditions designed using a D-optimal Design of Experiment (DoE). Analysis of Variance (ANOVA) was carried out to identify the most effective machining parameters on the responses of average grain size (AGS), machining temperature (MT), cutting force (CF), and feed force (FF). Next, Response Surface Method (RSM) was used to predict regression models of AGS, MT, CF, and FF. The optimal values of machining parameters were obtained to improve AGS, MT, CF, and FF. The ANOVA results showed that rake angle and cutting speed were, respectively, the most and least significant parameters affecting AGS in the design space. Rake angle was the most effective parameter influencing all of the responses. The single-criterion optimization of AGS provided a small improvement in AGS with a high increase in material removal rate (MRR). The results of the multi-criteria optimization of AGS, MT, CF, and FF demonstrated that machining of Ti6Al4V alloy with a tool having a medium cutting edge radius and high positive rake angle at a medium cutting speed and a low feed rate in the design space produced finer grains along with reduced CF and FF and an unchanged MT.

Design of a novel 3D ultrasonic vibration platform with tunable characteristics

Vibration-assisted tip-based nanofabrication techniques have advantages including increased material removal rate, reduced tip wear, and better material adaptability over traditional tip-based mechanical plowing. However, the influences of different vibration parameters on the machining efficiency are unclear, and how to select appropriate cutting parameters to guarantee the machined surface quality need further investigations. This paper introduces the design, modeling, and experimental validation of a novel 3D ultrasonic vibration platform with tunable characteristics. Moreover, multiple vibration modes including 1D (linear) and 2D (in-plane or out-of-plane) vibrations can be achieved. A novel flexure hinge, named T-shaped spatial flexure hinge is used to realize both in-plane and out-of-plane motions with a compact structure. Static modeling and dynamic modeling are conducted to guide the design process, and finite element analysis is utilized to verify the established model. Afterwards, a prototype is fabricated, and a number of experiments are implemented to validate the characteristics of the developed vibration platform. The experimental results show that different vibration modes can be achieved, and both the vibration amplitude and frequency can be set to an arbitrary value within a wide range according to the fabrication requirement. The maximum amplitude and frequency can reach around 50 nm and 20 kHz, i.e. ultrasonic frequency, respectively.

Experimental investigation and optimization of micro-drilling parameters on Inconel 800 superalloy

ABSTRACT This work presents the experimental study and optimizing the micro-drilling parameters on geometrical accuracy in micro-drilling on Inconel 800. The geometrical accuracy of the holes is incorporating circularity, overcut, hole damage factor, and taper ratio. In addition to that, material removal rate, machining time, and temperature are taken for study. Micro-holes, based on Taguchi orthogonal array (L27) design, are drilled on the workpiece of 2 mm thickness using uncoated tungsten carbide tools. Medium tool diameter, low spindle speed, and high feed rate resulted in the reduction in the magnitude of machining temperature, machining time, minimum circularity, overcut, hole damage factor, and taper ratio with increased material removal rate. The feed rate, tool diameter, and spindle speed are the order of the influencing parameter on the geometrical accuracy of the hole. The number of holes drilled before tool breakage is 120 in magnitude. Further, the increase in circularity error by 1.12%, overcut, and taper ratio decrease by 60% and 25% from 1st to 120th hole at an optimal level of medium tool diameter, low speed, and high feed rate. From the investigation, 0.8 mm tool diameter can be chosen for micro-drilling of cooling holes in jet engines, printed circuited boards, and biomedical elements.

An Analysis on the Parametric Optimization of Electrochemical Honing Process

Electrochemical honing (ECH) is a nontraditional machining process hybridizing the conjoint benefits of electrochemical machining (ECM) and mechanical honing actions. In this process, maximum amount of material is removed through anodic dissolution, followed by mechanical abrasion. In present day manufacturing industries, it has found wide ranging applications, mainly in finishing of varieties of gears, due to its various advantages, like increased material removal rate, long tool life, burr-free operation, achievement of higher surface finish and dimensional accuracy, generation of no residual stress, reduced noise, less material damage, etc. In order to achieve maximum machining capability from this process, it is always recommended to set its various input parameters at their optimal operating levels. In this paper, four powerful metaheuristic algorithms, i.e. firefly algorithm, differential evolution (DE) algorithm, cuckoo search (CS) algorithm and teaching–learning-based optimization (TLBO) algorithm are applied for single as well as multi-objective optimization of pulsed-ECH (PECH) and ECH processes. It is observed that TLBO algorithm supersedes other techniques in optimizing the two ECH processes with respect to the value of the derived optimal solution, consistency of the solutions and computational speed.

Optimization of Cutting Parameters for Sustainable Machining of Titanium Ti-5553 Alloy using Genetic Algorithm

Titanium Ti-5553 alloys have been considered as difficult-to-machine materials due to the extremely high tool wear, high cutting forces, high temperature, and poor surface quality of machined parts. Process parameters needs to be optimized in order to improve machining performance and in the meantime reducing manufacturing cost. This study proposes sustainable machining process for this new generation Titanium Ti-5553 alloy. Process parameters including depth of cut, cutting speed, and feed rate were taken into account to optimize parameters for reducing tool wear, energy consumption, and surface roughness, and in the meantime increase material removal rate. Genetic algorithm was utilized for optimizing the process parameters. Obtained results illustrated that optimization using genetic algorithm is a very effective approach to substantially improve machining performance of this alloy and make machining process of this alloy more sustainable by reducing energy consumption, manufacturing cost and increasing material removal rate in machining process of new generation titanium alloy.

Experimental investigation of the effect of tool material on the performance of AISI 4140 steel in the rotary near dry electrical discharge machining

This research conducts in three sections. The first section studies the effect of tool materials and gases on rotary workpiece electrical discharge machining. During the experiments, the effects of three kinds of tool materials (Cu, Cu-Cr, and Cu-Sn) and three types of industrial gases (air, argon, and CO2) on the material removal rate, tool wear rate, and workpiece surface roughness are investigated. The second is a comparison between rotary workpiece, rotary tool, and the fixed workpiece by choosing the appropriate tool material and gas in order to observe the effect of workpieces rotation on the process. Finally, another comparison has been done between wet electrical discharge machining and near dry electrical discharge machining of the fixed workpiece in order to study the effect of the dielectric. The results show the copper tool has the best performance compared with other tools. Scanning electron microscopy output shows the Cu-Sn tool creates shallow micro-cracks on the surface. Air and CO2 gases have the higher material removal rate in low current, but argon has better function than other gases in high current. In addition, a rotational speed causes an increase in material removal rate and tool wear rate and surface roughness decrease in near dry electrical discharge machining. The level of tool wear rate has decreased by 14% in the rotary workpiece compared with the rotary tool.

Removal Mechanism of Titanium Alloy Material in Ultrasound Vibration Drilling

In drilling the ultra-slim small diameter deep hole of titanium alloy, the problem of chip breaking and chip removal is common. When the drill is working normally, the ultrasonic vibration can be applied for the drill bit to cut the bit in the vibration to form a pulse. The cutting force waveform in drilling, should select the reasonable vibration frequency, amplitude, feed amount, workpiece rotation and other parameters to match, control the size and shape of the chip, get satisfactory chips, and avoid chip clogging. In this study, the ANSYS finite element simulation software was used to simulate the TC4 drilling process, and the difference between ultrasonic vibration drilling and ordinary drilling was analyzed. Drilling experiments were carried out. The experimental results show that compared with conventional drilling, ultrasonic vibration drilling has better surface quality, reduced tool wear and increased material removal rate.